edge_information["edge_patches"] can be None in cell_detection.py

[PingjunChen]

Describe the bug
Inside the function _clean_edge_cells of class CellPostProcessor inside cell_detection.py, it directly indexes the first element of edge_information["edge_patches"] via "edge_information["edge_patches"][0]", which can lead to an error, since the value of edge_information["edge_patches"] can be None, thus not subscriptable.

Screenshots

Additional context
This bug shall easily be resolved by adding a None value check before indexing the first element:

if edge_information["edge_patches"] is None:
    continue

[FabianHoerst]

Thanks for checking, I will put this on my list and check if this resolves the problem without any downstream error